Zn0.8Cd0.2S Hollow Spheres with a Highly Dispersed Ni Dopant for Boosting Photocatalytic Hydrogen Generation

Facilitating charge separation and increasing surface active sites have always been the goals of photocatalysis. Herein, we synthesized a Ni-doped Zn0.8Cd0.2S hollow sphere photocatalyst with a facile one-step hydrothermal method. Energy-dispersive spectroscopy mapping showed the high dispersion of Ni ions in the Zn0.8Cd0.2S hollow spheres. The experimental results confirmed that Ni doping reduced the band structure of the substrate, suppressed the recombination of photoinduced electrons and holes, and provided more reactive sites. Therefore, the photocatalytic activity had been greatly improved. As a consequence, the detected photocatalytic H-2 evolution rate increased up to 33.81 mmol.h(-1).g(-1) over an optimal Ni doping (5 wt %) of Zn0.8Cd0.2S hollow spheres, which was 20.87-fold higher than that of pure CdS. Elemental mapping showed that the Zn element was mainly distributed in the outermost layer of the hollow spheres; this might be the critical factor that enabled Ni-doped ZnxCd1-xS to maintain excellent stability.

Automated summary

The Ni-doped Zn0.8Cd0.2S hollow sphere photocatalyst achieved goals of promoting charge separation, increasing surface active sites, and enhancing photocatalytic activity. Ni doping reduced the band structure of the substrate, suppressed the recombination of photoinduced electrons and holes, and provided more reactive sites. The significant increase in photocatalytic H-2 evolution rate demonstrated the success of the Ni-doped ZnxCd1-xS for improved stability.